The present invention relates to a flotation device to float and separate the dissolved, suspended, sedimental solids within a waste water liquid.
Conventionally, recovery of heavy metals dissolved in waste water using precipitation of heavy metal compounds using chemicals addition, the precipitation by is accomplished utilizing base metal of the ionization tendency, and electrolysis. However, precipitation using chemicals has some problems of fractionation because the produced precipitates have special characteristics, and furthermore it is difficult to recover and give a dehydration treatment to the precipitated sludge. And as for precipitation utilizing base metal of the ionization tendency, generally it is not only inconsistent with the recovery percentage and the quality of recovered sludge, but also the precipitation speed gradually drops and makes it difficult to obtain a high recovery percentage. Further, as for the electrolysis method, there is a limit in it because as the quality of the heavy metal deteriorates, the electric current efficiency decreases, so greatly that sufficient recovery is not obtained. Besides these techinical problems, they need larger equipments compared with their treatment ability which result in greater expenses, so that it was desired that the pertiment treatment methods would be developed. And as another way, there is a floating methods to float by adding the aluminume chloride and the iron chloride to the waste water liquid to form hydroxide, feeding air to the waste water liquid thus formed hydroxide, mixing them to generate minute air bubbles, and making these air bubbles adhere to the hydroxide. In this method, the flocs of hydroxide even if adhered to the air bubbles, the adherence condition between them is unstable and the efficiency of flotation is bad, and has a disadvantage that the flocs are destroyed causing how the air bubbles are generated, it is difficult to re-treat the water once conducted flotation treatment as they were.